IPMatcher: Remove NetworkReality

IPMatcher's interface currently consists of a couple of static methods
that partly depend on the non-static class NetworkReality to enable mocking of DNS lookups.

This patch removes NetworkReality together with the static hostname glob matching method in
IPMatcher that used it.

This patch also renames a method from convertToIPv4IfPossible to
tryConvertToIPv4.

Acked-by: Tigran
Target: master
Require-book: no
Require-notes: no
pom: switch to jpnfs 0.5.2

update the nfs library with following fixes:

    [2b13212] nfsv41: consult backend 'filesystem' for read/write access
    [fedb335] nfsv41: propagate layout return errors on close

solves problem with file overwrite
solves problem with delayed checksum calculations on write

Ticket: #7572
Acked-by: Karsten Schwank
Target: master, 2.6
Require-book: no
Require-notes: yes